Conventional support and track systems for vertical blinds and draperies have included flat walled extrusions having horizontally extending and completely flat surfaces for supporting the wheels of a carrier. Draperies have included a narrower version of this structure, since draperies do not require a wider working area to support and house vertical blind actuating mechanical rod and gear structures.
The carriers for both draperies and vertical blinds have supported a completely horizontal axle for rotatable support of a wheel. The wheel width is quite thin, and the wheel width is one or two tens of magnitudes narrower than the carrier. Because the wheels have a narrow horizontal area, the tolerances between the carriers and the track have to be fairly close, not only to keep the carriers on track, but also to make certain that lateral forces on the vertical blind units or draperies will not cause the carriers to become untracked.
Part of this goal is achieved by having a relatively wide track and wide carrier, to provide bending moment resistance. However, the trend in window coverings is to try to provide a track which is as narrow as possible and as short as possible, so that a greater variety of window and window casement geometries can be accommodated. Narrower tracks and supported structures must not sacrifice their ability to effectively support and move the window covering structure, nor compromise structural integrity needed for long life and superior service.
Open windows are subjected to breezes and wind which can place significant lateral force on the window covering support devices supported by the track. Where the support devices cannot move somewhat laterally, they must be designed large enough and strong enough to directly fight the lateral forces, even to the point of failure. If the conventional track and support devices were enabled to allow lateral displacement, it would require the track to be pivotally mounted at the ends, causing an even larger track to prevent sagging in the middle, or require multiple pivotal mountings. Even this would not help where wind or breeze was providing force to one part of the structure alone, since the vertical blinds or window covering affected would bend against the track and the track would attempt to be angularly displaced, bending against the vertical blind portions not affected by the force of the breeze.
Once the breeze forces have subsided, both on conventional blinds and draperies, any angular displacement which has occurred, will remain. The draperies or vertical blinds will remain out of alignment, will look uneven, and may even be in ajammed position so that they will not operate properly to translatably support the vertical blind or drapery.
What is therefore needed is window covering system support structures which can permit lateral movement with respect to a rigidly mounted track, but which will allow the draperies and vertical blinds supported to come back into a straight alignment with respect to the track. Further, the inventive system should provide for a smaller drapery and curtain rod support and translation system in which the loads experienced by the parts thereof are better distributed and the parts thus have better integrity.
The needed system will enable a lesser tolerance between the track and the translating components, not only to provide clearance necessary to enable the supported draperies and vertical blinds to become laterally angularly displaced, with the support structures to be angularly displaced within the track, but without becoming dislodged from, jammed, or stuck with respect to the track.
The system should have axles and wheels which distribute the forces adequately and efficiently, and which, unlike conventional systems, prevent the binding or jamming of the leading edge of a wheel on one side of the carrier and the trailing edge of a wheel on the other side of the carrier from the carrier turning within its closely toleranced track.
In addition, the needed extrusion must be easy to make and should have as few sharp angles immediately adjacent the support track to enable more material to be employed for supporting the track. Conventional tracks have right angled edges of the wheels of the carrier running close to a right angled space within the carrier as much as possible. This requires any reinforcing material to be added to the outside of the track, making the track wider and thicker, rather than allowing it to be added to the inside, to add strength without adding external dimension.